The reliability of extreme surge levels,
estimated from observational records over
100 years
H.W. van den Brink, G.P. Konnen & J.D. Opsteegh
Royal Netherlands Meteorological Institute, The Netherlands
Abstract
Ensemble simulations with a total length of 5336 years were generated
with the KNMI General Circulation Model ECBilt, coupled with a simple
surge model to transform the wind field over the North Sea to the
surge level at Delfzijl (NL). The resulting skew surges were analysed with
the Generalized Extreme Value distribution to study the uncertainty in
surge level estimates with a return period of lo4 years, as derived from
observational records of order hundred years.
The 46 estimated surge levels with a return period of lo4 years, calculated
from sets of 116 year each, vary between 4.5 and 17 meters, with a
median of 8.5 meter. The 1 0 ~ - ~ e a r estimate of the 118-year observational
Delfzijl record (5.8 meter) fits well among these subsets, but this surge
level is considerably lower t